Effect of vitamin D supplementation on knee osteoarthritis: A systematic review and meta-analysis of randomized clinical trials

Clin Biochem. 2017 Dec;50(18):1312-1316. doi: 10.1016/j.clinbiochem.2017.09.001. Epub 2017 Sep 6.


Objective: To provide evidence regarding the effect of vitamin D supplementation on symptomatic knee osteoarthritis (OA).

Methods: A systematic review and meta-analysis was performed to quantitatively pool the results from randomized clinical trials. Studies were identified from a search of the Embase, MEDLINE and Web of Science databases up to January 22, 2017, and also from conference abstracts, ClinicalTrials.gov and the reference lists of identified studies. A standardized mean difference (SMD) was used to assess effect sizes, as outcomes were reported on different scales. Depending on the degree of heterogeneity, random-effects or fixed-effects models were used to pool outcomes.

Results: Up to January 22, 2017, four clinical trials containing 570 subjects in the vitamin D supplementation group and 560 subjects in the placebo group were identified. All of the included studies were of high quality and had a low risk of bias for each domain. The results indicated that vitamin D supplementation had a statistically significant but small-to-moderate effect on pain control in patients with knee OA (SMD=-0.32, 95% CI: -0.63 to -0.02). However, no effects were observed for the change in tibial cartilage volume (SMD=0.12, 95% CI: -0.05 to 0.29) or joint space width (SMD=0.07, 95% CI: -0.08 to 0.23). The subgroup analysis indicated that vitamin D supplementation had no significant effect regardless of whether patients had sufficient or insufficient serum 25(OH)D levels at baseline.

Conclusions: The results of this study indicate that vitamin D supplementation may not have a clinically significant effect on pain control or structure progression among patients with knee OA. Longer-term clinical trials with rigorous measurement of symptom and radiologic changes are required to further clarify the effect of vitamin D supplementation in patients with symptomatic knee OA and low serum 25(OH)D levels.

Keywords: Knee osteoarthritis; Randomized clinical trials; Vitamin D supplementation.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Female
  • Humans
  • Male
  • Osteoarthritis, Knee / blood
  • Osteoarthritis, Knee / drug therapy*
  • Osteoarthritis, Knee / physiopathology
  • Pain / blood
  • Pain / drug therapy
  • Pain / physiopathology
  • Pain Management / methods
  • Randomized Controlled Trials as Topic
  • Vitamin D / analogs & derivatives
  • Vitamin D / blood
  • Vitamin D / therapeutic use*


  • Vitamin D
  • 25-hydroxyvitamin D